Patent Literature 1 discloses a phenoxypyridine derivative having inhibitory activity against HGFR and being useful as an anti-tumor agent, inhibitor for angiogenesis or inhibitor for cancer metastasis.
wherein R1 is a 3- to 10-membered non-aromatic heterocyclic group or the like, R2 and R3 are each a hydrogen atom, R4, R5, R6 and R7 may be the same or different and are each a hydrogen atom, a halogen atom, a C1-6 alkyl group, or the like, R8 is a hydrogen atom or the like, R9 is a 3- to 10-membered non-aromatic heterocyclic group or the like, n is an integer of 1 to 2, and X is a group represented by a formula —CH═ or a nitrogen atom.
As the method for producing such a phenoxypyridine derivative, Patent Literature 1 describes, in Example 48, the following reaction in N,N-dimethylformamide in the presence of triethylamine and benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate.

Patent Literature 2 discloses the production method in which an aniline derivative and carboxylic acid derivative are reacted in the presence of a condensation agent as a method for producing the phenoxypyridine derivative suitable for industrial large scale synthesis.
wherein R1 is an azetidin-1-yl group optionally substituted with a substituent or the like, R2, R3, R4 and R5 may be the same or different and are each a hydrogen atom or a fluorine atom, and R6 is a hydrogen atom or a fluorine atom.
Patent Literature 3 discloses the production method shown in the following scheme as another method for producing the phenoxypyridine derivative.
wherein R1 is a 4-(4-methylpiperazin-1-yl)piperidin-1-yl group or a 3-hydroxyazetidin-1-yl group, R2, R3, R4 and R5 may be the same or different and are each a hydrogen atom or a fluorine atom, provided that two or three of R2, R3, R4 and R5 are a hydrogen atom, R6 is a hydrogen atom or a fluorine atom, R7 is a protection group for an amino group, and Ar is a phenyl group or the like.